feat: precompiled contract poc (#172)

* feat: App level precompile

* chore: Rename **2 variables to **Copied

store/cachekv/store.go

@@ -165,6 +165,37 @@ func (store *Store) CacheWrapWithTrace(w io.Writer, tc types.TraceContext) types
 	return NewStore(tracekv.NewStore(store, w, tc))
 }
 
+// Copy implements deep copy of CacheKVStore
+// TODO(dudong2): frequent calls to deep copy are a big bottleneck for performance, so need to benchmark
+func (store *Store) Copy() types.CacheKVStore {
+	store.mtx.Lock()
+	defer store.mtx.Unlock()
+
+	// deep copy of cValue
+	cacheCopied := make(map[string]*cValue, len(store.cache))
+	for key, val := range store.cache {
+		valueCopied := make([]byte, len(val.value))
+		copy(valueCopied, val.value)
+		cacheCopied[key] = &cValue{
+			value: valueCopied,
+			dirty: val.dirty,
+		}
+	}
+
+	// unsortedCache only track the key
+	unsortedCacheCopied := make(map[string]struct{}, len(store.unsortedCache))
+	for key := range store.unsortedCache {
+		unsortedCacheCopied[key] = struct{}{}
+	}
+
+	return &Store{
+		cache:         cacheCopied,
+		unsortedCache: unsortedCacheCopied,
+		sortedCache:   store.sortedCache.Copy(),
+		parent:        store.parent,
+	}
+}
+
 //----------------------------------------
 // Iteration
 

store/cachemulti/store.go

@@ -163,3 +163,23 @@ func (cms Store) GetKVStore(key types.StoreKey) types.KVStore {
 	}
 	return store.(types.KVStore)
 }
+
+// Copy returns an deep copy of CacheMultiStore
+// TODO(dudong2): frequent calls to deep copy are a big bottleneck for performance, so need to benchmark
+func (cms Store) Copy() types.CacheMultiStore {
+	// deep copy of CacheKVStore underlying CacheMultiStore
+	storesCopied := make(map[types.StoreKey]types.CacheWrap, len(cms.stores))
+	for key, store := range cms.stores {
+		if store, ok := store.(*cachekv.Store); ok {
+			storesCopied[key] = store.Copy()
+		}
+	}
+
+	return Store{
+		db:           cms.db.Copy(),
+		stores:       storesCopied,
+		keys:         cms.keys,
+		traceWriter:  cms.traceWriter,
+		traceContext: cms.traceContext,
+	}
+}

store/types/store.go

@@ -134,7 +134,8 @@ type MultiStore interface {
 // From MultiStore.CacheMultiStore()....
 type CacheMultiStore interface {
 	MultiStore
-	Write() // Writes operations to underlying KVStore
+	Write()                // Writes operations to underlying KVStore
+	Copy() CacheMultiStore // deep copy of CacheMultiStore
 }
 
 // CommitMultiStore is an interface for a MultiStore without cache capabilities.
@@ -244,6 +245,9 @@ type CacheKVStore interface {
 
 	// Writes operations to underlying KVStore
 	Write()
+
+	// deep copy of CacheKVStore
+	Copy() CacheKVStore
 }
 
 // CommitKVStore is an interface for MultiStore.